The collection and storage of viscous biologic samples, such as saliva, that are subject to degradation by bacteria and other organisms is a common problem. Viscous liquids are difficult to handle in pipettes and other apparatuses normally used with less viscous aqueous samples. The viscosity of the samples also makes it difficult to mix the samples with preservatives in order to protect against biologic breakdown. Such preservatives (or other materials, such as inhibitors of endogenous peptidases or other enzymes present in sample of biologic origin), which are often dried onto the surfaces of a container in which a non-viscous aqueous solution will be collected, cannot diffuse through a viscous liquid and therefore do not protect interior portions of the liquid against bacterial action.
A number of systems have been developed for handling viscous liquids, particularly saliva and blood serum. See, for example, Haldopoulos, U.S. Pat. No. 3,832,141; Ohringer, U.S. Pat. No. 3,846,077; Breno, U.S. Pat. No. 4,209,488; Mar, U.S. Pat. No. 4,644,807; Romer, U.S. Pat. No. 4,895,808; and Seymour, U.S. Pat. No. 5,268,148. However, those apparatuses that have previously been developed in this field are generally sophisticated devices intended for use by a skilled laboratory technician. The present invention was made with an unskilled user in mind, particularly an untrained patient collecting a saliva sample or similar fluid sample at home in the absence of any training or instruction other than written instructions that will accompany a kit. It is this need for a simplified and easy-to-use collection kit for the collection and storage of viscous fluids, such as saliva, that has led the present invention.